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International audience; Mg 3 (BH 4) 4 (NH 2) 2 compound was synthesized through the investigation of the Mg(BH 4) 2-Mg(NH 2) 2 phase diagram; its crystal structure was solved in a tetragonal unit cell with the space group I4̅. Interestingly, Mg 3 (BH 4) 4 (NH 2) 2 has a high thermal stability with a decomposition temperature above 190°C and exhibits a high Mg 2+ ionic conductivity of 4.1 × 10 −5 S•cm −1 at 100°C with a low activation energy (0.84 eV). The reversible Mg deposition/stripping was demonstrated at 100°C when using Mg 3 (BH 4) 4 (NH 2) 2 as solid electrolyte. Thus, Mg 3 (BH 4) 4 (NH 2) 2 is a compound that could help to develop rechargeable Mg-ion solid-state batteries.

The formation phenomena of silver carbonate (Ag2CO3)–silver iodide (AgI) solid solutions were investigated by X-ray diffraction, thermogravimetry-differential thermal analysis, and electrical conductivity measurement. Results revealed that AgI and Ag2CO3 reacted with each other when mixed at room temperature. The reaction products were classified into three types: (1) AgI-based solid solutions in the AgI-rich region for x = 10% or less in x Ag2CO3–(1 − x) AgI; (2) Ag2CO3-based solid solutions in the Ag2CO3-rich region for x = 60% or more; and (3) silver carbonate iodides in the intermediate range for x between 10% and 60%. For the AgI-based solid solutions, the incorporation of Ag2CO3 into the AgI lattice expanded the unit cell and enhanced electrical conductivity. The solubility limit of Ag2CO3 into the AgI lattice estimated from the differential thermal analysis was x ≈ 5%.

In this work, a new type of addition reaction between La(BH4)3 and LiX, X = Cl, Br, I, is used to synthesize LiLa(BH4)3Cl and two new compounds LiLa(BH4)3X, X = Br, I. This method increases the amounts of LiLa(BH4)3X and the sample purity. The highest Li-ion conductivity is observed for LiLa(BH4)3Br, 7.74 × 10-5 S/cm at room temperature (RT) and 1.8 × 10-3 S/cm at 140°C with an activation energy of 0.272 eV. Topological analysis suggests a new lithium ion conduction pathway with two new different types of bottleneck windows. The sizes of these windows reveal an opposite size change with increasing lattice parameter, that is, increasing size of the halide ion in the structure. Thus, we conclude that the sizes of both windows are important for the lithium ion conduction in LiLa(BH4)3X compounds. The lithium ion conductivity is measured over one to three heating cycles and with different contacts (gold or carbon) between the electrodes and the electrolyte. Moreover, 11B MAS NMR is used to verify the contents of the samples, whereas thermogravimetric analysis shows 4.8 and 3.6 wt % of hydrogen release for LiLa(BH4)3Cl and LiLa(BH4)3Br in the temperature range RT to 400°C. (Graph Presented).

Solid inorganic and polymeric electrolytes have the potential to enable rechargeable batteries with higher energy densities, compared to current lithium-ion technology, which uses liquid electrolyte. Inorganic materials such as ceramics and glasses conduct lithium ions well, but they are brittle, which makes incorporation into a battery difficult. Polymers have the flexibility for facile use in a battery, but their transport properties tend to be inferior to inorganics. Thus, there is growing interest in composite electrolytes with inorganic and organic phases in intimate contact. This article begins with a discussion of ion transport in single-phase electrolytes. A dimensionless number (the Newman number) is presented for quantifying the efficacy of electrolytes. An effective medium framework for predicting transport properties of composite electrolytes containing only one conducting phase is then presented. The opportunities and challenges presented by composite electrolytes containing two conducting phases are addressed. Finally, the importance and status of reaction kinetics at the interfaces between solid electrolytes and electrodes are covered, using a lithium-metal electrode as an example.

As an ionic conductive functional layer of intermediate temperature solid oxide fuel cells (ITSOFC), samarium-doped ceria (SDC)–LiNaSO4 nano-composites were synthesized by a sol–gel method and their properties were investigated. It was found that the content of LiNaSO4 strongly affected the crystal phase, defect concentration, and conductivity of the composites. When the content of LiNaSO4 was 20 wt%, the highest conductivity of the composite was found to be, respectively, 0.22, 0.26, and 0.35 S cm−1 at temperatures of 550, 600, and 700 °C, which are much higher than those of SDC. The peak power density of the single cell using this composite as an interlayer was improved to, respectively, 0.23, 0.39, and 0.88 W cm−2 at 500, 600, and 700 °C comparing with that of the SDC-based cell. Further, the SDC–LiNaSO4(20 wt%)-based cell also displayed better thermal stability according to the performance measurements at 560 °C for 50 h. These results reveal that SDC–LiNaSO4 composite may be a potential good candidate as interlayer for ITSOFC due to its high ionic conductivity and thermal stability.

[EN] Increased availability of methane from shale gas and stranded gas deposits in the recent years may facilitate the production of ethylene by means of potentially more competitive routes than the state-of-the-art steam cracking processes. One appealing route is the oxidative coupling of methane (OCM), which is considered in this work for the production of ethylene by means of the use of catalytic membrane reactors (CMR) based on Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) ceramic material. In a first approach, a screening of 15 formulations as catalysts for the ethylene-ethane production was conducted on CMR consisting of disk-shaped planar BSCF membranes. At 900 degrees C, the maximum C-2 selectivity was 70%, reached with Ba0.5Sr0.5FeO3-delta and La0.5Ce0.1Sr0.4Co0.8Fe0.2O3-delta catalysts. On the other hand, low CH4 conversions (X-CH4) resulted in C-2 yields below 3%. Operation at 1,000 degrees C significantly shifted X-CH4 for all the activated membranes due to the decrease in CH4/O-2 ratios, thus obtaining C-2 yields close to 9% and productivities of ca. 1.2ml.min(-1).cm(-2) with Ce0.9Gd0.1O2-delta and Ba0.5Sr0.5Co0.8Fe0.2O3-delta impregnated with Mn-Na2WO4 catalysts. The performance of OCM reaction was also studied in a tubular catalytic membrane reactor. Tubular configuration improved C-2 yield by minimizing CH4/O-2 ratios up to 1.7, obtaining a maximum of 15.6% at 900 degrees C with a BSCF capillary membrane activated with a packed bed of 2 wt% Mn/5 wt% Na2WO4 on SiO2 catalyst., Financial support by the Spanish Government (ENE2014-57651 and SEV-2012-0267 grants) and by the EU through FP7 GREEN-CC Project (GA 608524), is gratefully acknowledged. The authors want also acknowledge the Electron Microscopy Service from the Universitat Politecnica de Valencia for their support in the SEM analysis performed in this work.

LaW x Nb 1−x O 4+x/2 ceramics (x = 0.16) were prepared via a solid state route and studied with respect to phase stability and mixed ionic and electronic conductivity under conditions of technological relevance for fuel cell applications. The chemical compatibility against standard cathode materials revealed that Sr-doped LaMnO 3 could be used without detectable chemical interaction up to at least 1000 °C. Impedance spectroscopy measurements performed in the range 400–850 °C, using different atmospheres (air and N 2 +H 2 , both dry and water vapour saturated), suggest oxygen transport numbers equal to 1 under oxidising conditions, and decreasing when exposed to extreme reducing conditions. The total conductivity at 800 °C increases from 1.4·10 −3 S cm −1 in air to 2.5·10 −3 S cm −1 in wet hydrogen and 6.1·10 −3 S cm −1 in dry hydrogen, but the observed onset of n-type conductivity has little practical impact under typical fuel cell operating conditions.

This work reports on the investigation of CO 2 selective membranes for pre-combustion and post- combustion processes, in which CO 2 is extracted from multi-component gas streams at intermediate temperature (400 – 600 °C). The dual-phase membranes developed in this work are designed as a porous oxide ion conducting ceramic matrix, which is infiltrated with a molten carbonate phase. Both ex-situ and in-situ characterization methods were used to study disk shaped and tubular membranes. The gas transport properties of disk-shaped membranes were further investigated under various operating conditions relevant for both post-combustion and pre-combustion applications.

Lithium superionic conductors with the Li10GeP2S12 (LGPS)-type structure are promising materials for use as solid electrolytes in next-generation lithium batteries. A novel member of the LGPS family, Li9.42Si1.02P2.1S9.96O2.04, and its solid solutions were synthesised by quenching from 1273 K in the Li2S–P2S5–SiO2 pseudoternary system. The material exhibited an ionic conductivity as high as 3.2×10−4 S cm−1 at 298 K, as well as the high electrochemical stability to lithium metal, which was improved by the introduction of oxygen into the LGPS-type structure. An all-solid-state cell with a lithium metal anode and Li9.42Si1.02P2.1S9.96O2.04 as the separator showed excellent performance with a high coulomb efficiency of 100%. Thus, oxygen doping is an effective way of improving the electrochemical stability of LGPS-type structure.

Rapidly growing attention is being recently directed towards the investigation of the ionic conducting properties of oxide film hetero-structures. Experimental evidence has been reported showing that interfacial phenomena at hetero-phase interfaces give rise to faster ion conduction pathways than the bulk or homo-phase interfaces. Nonetheless, a deeper understanding of the interface transport properties is still needed to exploit these effects. In this work we have investigated the growth mechanism of different superlattices fabricated by pulsed laser deposition (PLD) coupling doped and undoped cerium and zirconium oxides. Single crystalline MgO wafers were selected as deposition substrates. The superlattice structures were obtained by means of a thin buffer layer of SrTiO3 (STO). The growth mechanism was investigated by reflection high energy electron diffraction (RHEED) and X-ray diffraction (XRD) analyses.

Ionic liquid (IL) based gel polymer electrolytes (GPEs) are being investigated extensively at present as substitutes for conventional GPEs based on a polymer, a salt and solvents. The main reason behind this is the drawbacks in usage of solvents. IL based GPEs have been employed for energy storage devices such as batteries and super capacitors due to their interesting mechanical, physical and electrochemical properties. This study focused on synthesis preparation and characterization of an IL based GPE consisting of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-co-HFP), zinc trifluoro metha -nesulfonate (Zn(CF3SO3)2 - ZnTF) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF). Thin film samples were prepared using solvent casting method. The optimized composition was found to be 1 PVdF-co-HFP: 1 1E3MITF: 3 ZnTF (by weight basis). This mechanically stable, thin film has the maximum room temperature conductivity of 7.42×10-3 S cm-1. Conductivity variation with temperature follows Vogel - Tamman - Fulcher (VTF) behavior confirming the relation of conductivity mechanism with the free volume theory. The IL based GPE is a purely an ionic conductor having a considerable anionic contribution. It shows stability up to 2.5 V which is very much convenient from a practical point of view. Oxidation and reduction of Zn takes place at the potentials of 0.5 V and –0.5 V, respectively. In addition, Zn platting and stripping occurs only on the Zn electrodes but not on the stainless steel (SS) electrodes. Impedance measurements taken for the GPE continuously for a long period of time exhibited a satisfactory stability with Zn electrodes.

The single component fuel cell (SCFC) is a novel physical-electrochemical device for energy conversion which is recently discovered. The functional composite materials of Li0.15Ni0.25Cu0.3Zn0.3O2-delta (LNCZO) and Ce0.8Sm0.2O1.9 (SDC)-carbonate are proved as unique materials in SCFC (or one-layer fuel cell). In this work, the microstructure and morphology of two composite materials of LNCZO-SDC-Na2CO3 (LNCZO-NSDC) and LNCZO-SDC-(Li/ Na)(2)CO3 (LNCZO-LNSDC) are investigated by SEM-EDX and HR-TEM. Their catalytic activities for both hydrogen oxidation and oxygen reduction are studied by H-2-TPR and O-2-TPD, respectively. It is discovered for the first time that binary carbonates as ionic conductor mixing with semiconductor homogenously help to form unique semiconducting-ionic microstructure. The particle arrangement and interface conduction in the microstructure significantly influences on the SCFC performances due to different catalytic activity and polarization resistance. Even this, O-2 reduction reaction (ORR) for the single homogeneous layer still predominates in the redox reaction and binary carbonates are in favor of the oxygen conduction and desorption. These fin dings are essential to exactly understand the connections among structure, catalytic activities and performances underlying SCFC. QC 20150109

Solid oxide fuel cells (SOFCs) offer an efficient energy conversion technology for alleviating current energy problems. High temperature proton-conducting (HTPC) oxides are promising electrolytes for this technology, since their activation energy is lower than that of conventional oxygen-ion conductors, enabling the operating temperature reduction at 600 °C. Among HTPC oxides, doped BaZrO3 materials possess high chemical stability, needed for practical applications. Though, poor sinterability and the resulting large volume of highly resistive grain boundaries hindered their deployment for many years. Nonetheless, the recently demonstrated high proton conductivity of the bulk revived the attention on doped BaZrO3, stimulating research on solving the sintering issues. The proper selection of dopants and sintering aids was demonstrated to be successful for improving the BaZrO3 electrolyte sinterability. We here briefly review the synthesis strategies proposed for preparing BaZrO3-based nanostructured powders for electrolyte and electrodes, with the aim to improve the SOFC performance.

Thermogravimetric analysis (TGA) technique in controlled oxygen partial pressure (pO 2) atmospheres has been used to obtain equilibrium oxygen content data as a function of pO 2 on the La 2Mo 2O 9-δ system resulting from the partial reduction of fast oxide-ion conductor La 2Mo 2O 9 (LM). Thermodynamic conditions for stabilization of crystalline La 7Mo 7O 30 and amorphous La 2Mo 2O 7-y at 718 °C have been determined and discussed. At 608 °C, the compound reported for the first time La 2Mo 2O 8.96 (LM896) has been found. The crystalline form and transition temperature in LM896 have been identified by X-ray diffraction at room temperature (XRD) and at controlled temperature. Conductivity curves obtained by electrochemical impedance spectroscopy (EIS) as a function of temperature for both LM and LM896 have been compared. The results indicate that LM896 is a mixed ionic and electronic conductor (MIEC). © 2012 The Royal Society of Chemistry. Fil: Vega Castillo, Jesus Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina Fil: Ravella, Uday K.. Université du Maine; Francia Fil: Corbel, Gwenaël. Université du Maine; Francia Fil: Lacorre, Philippe. Université du Maine; Francia Fil: Caneiro, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina

Melilite-type [A(2)](2)[B(I)](2)[B(II)(2)O(7)](2) gallates are promising ion conducting electrolytes for deployment in solid oxide fuel cells. Single crystals of [CaLa](2)[Ga](2)[Ga(2)O(7)](2), grown in an optical floating zone furnace, were investigated using a combination of transmission electron microscopy and single crystal X-ray diffraction. Strong anisotropic displacements of oxygen arise from the structural misfit between the interlayer Ca/La cations and the [Ga]-[Ga(2)O(7)] tetrahedral layers. A model employing two-dimensional modulation achieves bond lengths and bond angles that preserve satisfactory bond valence sums throughout the structure. The melilite belongs to the tetragonal superspace group P42(1)m(α, α, 0)00s(α, α, 0)000, α = 0.2160(5), with a subcell metric of a = 7.9383(2) A, c = 5.2641(3) A, onto which modulation vectors are superimposed: q(1) = α (a* + b*), q(2) = α (-a* + b*). Both displacive (cation and anion) and occupational (cation) modulations contribute to incommensuration. The analysis of structural adjustments that accompany changes in temperature and composition provides assurance that the crystal chemical model is correct. By better understanding the flexibility of this modulated structure a rational approach toward crystallochemical optimization of electrolyte performance by enhancing oxygen mobility becomes feasible.

This paper presents results for the conductivity of BaCe0.85Y0.15O2-δ (BCY15) measured by electrochemical impedance spectroscopy in wet hydrogen and in Air, as well as test results from the application of the material in a new dual membrane fuel cell configuration (“IDEAL Cell”), in which the water is produced and evacuated through a separate chamber. The conductivity of dense BCY15 in wet hydrogen atmosphere at 700 °C is 2.0 10-2 S/cm. The measured values in air are of the same order. Preliminary tests of the material in the new cell design, where the three types of conductivity (protonic, oxide ion and mixed) are used in different cell compartments, are successfully performed.

International audience; Platinum nanoparticles were dispersed by wet impregnation on YSZ (8 mol% Y2O3) an ionically conducting support. The Pt dispersion of a series of catalysts was determined by using H-2 pulse chemisorption. Temperature Programmed Reduction (TPR) experiments were performed to characterize the pre-reduction step before dispersion measurements. Finally, a fast and reliable procedure was defined for the Pt dispersion measurements consisting in a pre-reduction step in hydrogen at 500 degrees C before the H-2 pulse chemisorption performed at -28 degrees C. Reproducible Pt dispersion values were obtained in good agreement with those measured by pulse CO chemisorptions and static volumetric titration. In addition, the combination of Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and TPR has evidenced the role of surface oxygen vacancies on YSZ support for both H-2 and CO chemisorptions.

Pulsed Laser Deposition technique was used to engineer heterostructures of Yttrium-stabilized Zirconia (YSZ) and Gadolinium-doped Ceria (GDC) on perovskite substrates like Neodymium Gallate (NGO) and Strontium Titanate (STO). Epitaxial superlattices of the same number of layers of both materials were deposited with each block thickness as thin as 2 unit cells up to 30 unit cells. X-ray diffraction (XRD) investigation of the (002) symmetrical reflection allowed to evaluate the amount of material deposited in each layer constituting the superlattices. (113) asymmetrical reflections were analyzed to investigate strain effects on YSZ and GDC lattice parameters, evidencing the cube on cube growth of these films.

[ES] En este trabajo se presentan los resultados preliminares sobre películas delgadas de YSZ obtenidas mediante la nueva técnica de MOCVD de inyección pulsada para su aplicación como electrolitos sólidos. La originalidad de esta técnica consiste en la preparación e introducción de la fase vapor que se realiza mediante la inyección pulsada de micro-gotas de la solución líquida, que contiene los precursores de los elementos a depositar, dentro de la zona de reacción. Las características de la gota: tamaño, concentración de la solución y frecuencia de inyección determinan el espesor y la micro-estructura de las capas obtenidas. Este método, además de muy reproducible, permite obtener fácilmente estructuras multicapas con bajos ritmos de crecimiento para epitaxias o con altos ritmos de crecimiento para la obtención de heteroestructuras. Se ha puesto a punto esta técnica para la obtención de capas densas de YSZ (circona estabilizada con itria), material comúnmente utilizado como electrolito sólido de alta temperatura en sondas de oxígeno, generadores de oxígeno y SOFC (pilas de combustible de estado sólido). Se pretende obtener dichos dispositivos en forma de multicapas del tipo ánodo/electrolito/cátodo. Para ello, se han depositado capas de YSZ sobre silicio para optimizar los parámetros de depósito pero también sobre sustratos porosos activos que puedan actuar como electrodo en los dispositivos anteriormente descritos., [EN] In this work, we describe the preparation of YSZ layers on porous and non-porous substrates using the Pulsed Injection MOCVD technique for solid electrolyte applications. In this technique, the vapour phase is obtained by injecting micro-droplets of the desired solution delivered from a container kept at room temperature into a heated evaporator connected to a deposition chamber. The droplet characteristics, volume, precursor concentration and injection frequency will control and determine the thickness and the microstructure of the layers. The system offers a high degree of repeatability of the liquid volume injected and thus a high reproducibility of the layers from low to high growth rates. This process has been optimised in order to obtain dense YSZ membranes to be used as solid electrolytes in SOFC, oxygen generators and oxygen sensors. Future work will consist in the preparation of anode-electrolyte-cathode multilayered devices. For this purpose, experimental parameters have been studied and optimised in order to obtain thin YSZ membranes on dense and porous substrates., Este trabajo ha sido parcialmente financiado por la red temática europea Multimetox G5RT-CT-2000-05001.

BaMMn7O16 (M = Mg, Mn, Fe, Ni) and AMn8O16 (A = Ba, K2) hollandite oxides were synthesized in air from metal carbonates and a mixture of simple oxides using the thermal decomposition in solid phase method at 850 C. The oxides BaMn8O16 and BaFeMn7O16 crystallized in the hollandite monoclinic phase, S.G. I2/m and S.G. P2(1)/n respectively, whereas K2Mn8O16 was tetragonal, S.G. I4/m. Two new phases are reported: BaMgMn7O16 and BaNiMn7O16 which crystallize in the hollandite monoclinic phase structure. The ionic distributions were proposed on the basis of several physicochemical analyses comporting XRD, GTA, magnetic susceptibility and oxidation power measurements. Barium and potassium manganites showed Mn3+ and Mn4+ in octahedral sites whereas BaMMn7O16 (M = Mg, Ni) exhibited Mn2+ and Mn4+ in sites B. On the other hand, iron-manganese hollandite, BaFeMn7O16, shows Fe3+ ions besides Mn3+ and Mn4+ cations Se sintetizaron a 850 ºC en aire , óxidos de estructura holandita de fórmula BaMMn7O16 (M = Mg, Mn, Fe, Ni) y AMn8O16 (A = Ba,K2), usando como precursores carbonatos metálicos y una mezcla de óxidos simples, mediante la técnica de descomposición térmica en fase sólida. Los óxidos BaMn8O16 and BaFeMn7O16 cristalizaron en la fase holandita monoclínica, grupo espacial I2/m y P2(1)/n respectivamente, mientras que el óxido K2Mn8O16 presenta una estructura holandita tetragonal, grupo espacial I4/m. Se informa de dos nuevos óxidos, BaMgMn7O16 y BaNiMn7O16, que cristalizaron en la estructura holandita monoclínica. Se proponen las respectivas distribuciones iónicas sobre la base de análisis fisicoquímicos como: DRX, ATG, susceptibilidad magnética y poder de oxidación. Manganitas de bario y de potasio presentan en los sitios octaédricos de la estructura los iones Mn3+ y Mn4+ mientras que los óxidos de fórmula general BaMMn7O16 (M = Mg, Ni) muestran iones Mn2+ and Mn4+ en tales sitios. Por otra parte, el óxido BaFeMn7O16 presenta además de los iones Mn3+ y Mn4+, los iones Fe3+ en los sitios octaédricos B estructurales

The first-order Raman spectrum of K 2 S was measured over the temperature range from 10 to 742 K. The temperature dependence of the linewidth can be explained using results from the anharmonic lattice dynamics approach. Both the cubic and the quartic anharmonic interactions are of importance for this system. At 293 K, the Raman line is at ω T 2g =128 cm −1 with a full width at half maximum Γ T 2g =2.9 cm −1 .

International audience; The electrical study of lithium boracites, which are electronic insulators, shows a high mobility of the Li+ cation. They are the first high isotropically conducting Li compounds.

A general, efficient and experimentally simple method for the synthesis of covalently crosslinked class II hybrid polymers based on PolyEtherEtherKetone (PEEK) with a high degree of sulfonation (DS = 0.8) was performed. The synthetic strategy foreseen two steps: the first one, direct sulfonation, led to the introduction of sulfonic acid groups and to the formation of sulfone bridges among repeat units. The second step, lithiation and silylation, led to the formation of covalent bonds between the organic backbone and Si(OH)3 moieties. The materials were characterized by 1H NMR Spectroscopy, ATR/FTIR Spectroscopy, Thermogravimetric Analysis (TGA) and Mass Spectrometry. Preliminary proton conduction measurements in dry conditions were performed. The introduction of silicon groups in the system improved thermal stability.